1591874991 has 32 divisors (see below), whose sum is σ = 2721438720. Its totient is φ = 900800352.

The previous prime is 1591874899. The next prime is 1591874993. The reversal of 1591874991 is 1994781951.

1591874991 is a `hidden beast` number, since 1 + 591 + 8 + 7 + 49 + 9 + 1 = 666.

It is not a de Polignac number, because 1591874991 - 2⁷ = 1591874863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1591874993) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21420 + ... + 60353.

It is an arithmetic number, because the mean of its divisors is an integer number (85044960).

Almost surely, 2^1591874991 is an apocalyptic number.

1591874991 is a deficient number, since it is larger than the sum of its proper divisors (1129563729).

1591874991 is a wasteful number, since it uses less digits than its factorization.

1591874991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81892 (or 81886 counting only the distinct ones).

The product of its digits is 816480, while the sum is 54.

The square root of 1591874991 is about 39898.3081220244. The cubic root of 1591874991 is about 1167.6239286910.

It can be divided in two parts, 15918 and 74991, that added together give a palindrome (90909).

The spelling of 1591874991 in words is "one billion, five hundred ninety-one million, eight hundred seventy-four thousand, nine hundred ninety-one".